Transmission Not Go Into Gear problems of the 2006 Mercedes Benz ML500

Sporadically, while driving along on local roads or the highway, the car's transmission does not switch higher than third gear. The problem occurs about once a month. Upon engine restart, vehicle drives properly. My pedal shifters do not work when this problem occurs; I can try to shift gears with the pedal shifters, and the software indicates a change from 3rd to 4th gear, but the actual transmission does not change gears. It remains stuck in third gear whether I speed up or slow down. If I place the vehicle in park and try to reverse, there is no power to the vehicle until I restart the car. This seems to be occurring with more and more frequency. I have a safety concern that I have to pull off the road and restart my car whenever this occurs. This seems to be problematic for several owners on the NHTSA site and online.

Accelerated after stopping at a lighted intersection. The transmission would not shift into gear therefore, the vehicle would not move. Vehicle was taken to dealer who replaced the transmission at the reduced cost of $2500, as a courtesy, since the vehicle was out of warranty by 3k miles.